T'was not I!

Wasn't me. It was posted by one Jacques Jost in January 2006 and unfortunately I have no knowledge of the pic you're referring to.

As far as your other query is concerned - let me complete the paragraph,sadly the only reference to the 3rd Cavalry's Marmon Herringtons in John Gaylor's book:

"...they (3rd Cavalry) arrived in Penang on the 28 Nov 41, a week before the Japanese invasion. Singapore ordnance depot issued thirty Marmon-Herrington armoured cars on the 8th December, the Japanese having landed on the east coast the previous night. Withdrawal down the Malay Peninsula followed and the entire force was captured on Singapore Island in February, 1942."